diff options
| -rw-r--r-- | src/Makefile.am | 2 | ||||
| -rw-r--r-- | src/util/tokenpipe.cpp | 108 | ||||
| -rw-r--r-- | src/util/tokenpipe.h | 127 |
3 files changed, 237 insertions, 0 deletions
diff --git a/src/Makefile.am b/src/Makefile.am index 8a9ef49a34..6a7a49f012 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -249,6 +249,7 @@ BITCOIN_CORE_H = \ util/system.h \ util/threadnames.h \ util/time.h \ + util/tokenpipe.h \ util/trace.h \ util/translation.h \ util/ui_change_type.h \ @@ -577,6 +578,7 @@ libbitcoin_util_a_SOURCES = \ util/strencodings.cpp \ util/string.cpp \ util/time.cpp \ + util/tokenpipe.cpp \ $(BITCOIN_CORE_H) if USE_LIBEVENT diff --git a/src/util/tokenpipe.cpp b/src/util/tokenpipe.cpp new file mode 100644 index 0000000000..79465dd430 --- /dev/null +++ b/src/util/tokenpipe.cpp @@ -0,0 +1,108 @@ +// Copyright (c) 2021 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. +#include <util/tokenpipe.h> + +#include <config/bitcoin-config.h> + +#ifndef WIN32 + +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> + +TokenPipeEnd TokenPipe::TakeReadEnd() +{ + TokenPipeEnd res(m_fds[0]); + m_fds[0] = -1; + return res; +} + +TokenPipeEnd TokenPipe::TakeWriteEnd() +{ + TokenPipeEnd res(m_fds[1]); + m_fds[1] = -1; + return res; +} + +TokenPipeEnd::TokenPipeEnd(int fd) : m_fd(fd) +{ +} + +TokenPipeEnd::~TokenPipeEnd() +{ + Close(); +} + +int TokenPipeEnd::TokenWrite(uint8_t token) +{ + while (true) { + ssize_t result = write(m_fd, &token, 1); + if (result < 0) { + // Failure. It's possible that the write was interrupted by a signal, + // in that case retry. + if (errno != EINTR) { + return TS_ERR; + } + } else if (result == 0) { + return TS_EOS; + } else { // ==1 + return 0; + } + } +} + +int TokenPipeEnd::TokenRead() +{ + uint8_t token; + while (true) { + ssize_t result = read(m_fd, &token, 1); + if (result < 0) { + // Failure. Check if the read was interrupted by a signal, + // in that case retry. + if (errno != EINTR) { + return TS_ERR; + } + } else if (result == 0) { + return TS_EOS; + } else { // ==1 + return token; + } + } + return token; +} + +void TokenPipeEnd::Close() +{ + if (m_fd != -1) close(m_fd); + m_fd = -1; +} + +std::optional<TokenPipe> TokenPipe::Make() +{ + int fds[2] = {-1, -1}; +#if HAVE_O_CLOEXEC && HAVE_DECL_PIPE2 + if (pipe2(fds, O_CLOEXEC) != 0) { + return std::nullopt; + } +#else + if (pipe(fds) != 0) { + return std::nullopt; + } +#endif + return TokenPipe(fds); +} + +TokenPipe::~TokenPipe() +{ + Close(); +} + +void TokenPipe::Close() +{ + if (m_fds[0] != -1) close(m_fds[0]); + if (m_fds[1] != -1) close(m_fds[1]); + m_fds[0] = m_fds[1] = -1; +} + +#endif // WIN32 diff --git a/src/util/tokenpipe.h b/src/util/tokenpipe.h new file mode 100644 index 0000000000..f56be93a38 --- /dev/null +++ b/src/util/tokenpipe.h @@ -0,0 +1,127 @@ +// Copyright (c) 2021 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#ifndef BITCOIN_UTIL_TOKENPIPE_H +#define BITCOIN_UTIL_TOKENPIPE_H + +#ifndef WIN32 + +#include <cstdint> +#include <optional> + +/** One end of a token pipe. */ +class TokenPipeEnd +{ +private: + int m_fd = -1; + +public: + TokenPipeEnd(int fd = -1); + ~TokenPipeEnd(); + + /** Return value constants for TokenWrite and TokenRead. */ + enum Status { + TS_ERR = -1, //!< I/O error + TS_EOS = -2, //!< Unexpected end of stream + }; + + /** Write token to endpoint. + * + * @returns 0 If successful. + * <0 if error: + * TS_ERR If an error happened. + * TS_EOS If end of stream happened. + */ + int TokenWrite(uint8_t token); + + /** Read token from endpoint. + * + * @returns >=0 Token value, if successful. + * <0 if error: + * TS_ERR If an error happened. + * TS_EOS If end of stream happened. + */ + int TokenRead(); + + /** Explicit close function. + */ + void Close(); + + /** Return whether endpoint is open. + */ + bool IsOpen() { return m_fd != -1; } + + // Move-only class. + TokenPipeEnd(TokenPipeEnd&& other) + { + m_fd = other.m_fd; + other.m_fd = -1; + } + TokenPipeEnd& operator=(TokenPipeEnd&& other) + { + Close(); + m_fd = other.m_fd; + other.m_fd = -1; + return *this; + } + TokenPipeEnd(const TokenPipeEnd&) = delete; + TokenPipeEnd& operator=(const TokenPipeEnd&) = delete; +}; + +/** An interprocess or interthread pipe for sending tokens (one-byte values) + * over. + */ +class TokenPipe +{ +private: + int m_fds[2] = {-1, -1}; + + TokenPipe(int fds[2]) : m_fds{fds[0], fds[1]} {} + +public: + ~TokenPipe(); + + /** Create a new pipe. + * @returns The created TokenPipe, or an empty std::nullopt in case of error. + */ + static std::optional<TokenPipe> Make(); + + /** Take the read end of this pipe. This can only be called once, + * as the object will be moved out. + */ + TokenPipeEnd TakeReadEnd(); + + /** Take the write end of this pipe. This should only be called once, + * as the object will be moved out. + */ + TokenPipeEnd TakeWriteEnd(); + + /** Close and end of the pipe that hasn't been moved out. + */ + void Close(); + + // Move-only class. + TokenPipe(TokenPipe&& other) + { + for (int i = 0; i < 2; ++i) { + m_fds[i] = other.m_fds[i]; + other.m_fds[i] = -1; + } + } + TokenPipe& operator=(TokenPipe&& other) + { + Close(); + for (int i = 0; i < 2; ++i) { + m_fds[i] = other.m_fds[i]; + other.m_fds[i] = -1; + } + return *this; + } + TokenPipe(const TokenPipe&) = delete; + TokenPipe& operator=(const TokenPipe&) = delete; +}; + +#endif // WIN32 + +#endif // BITCOIN_UTIL_TOKENPIPE_H |